Heat dissipation device

ABSTRACT

A heat dissipation device for placing on a heating element is disclosed. The heat dissipation device includes a base and a plurality of fin assemblies. The base includes a plurality of slots. Each fin assembly includes a fixed portion and a fin portion connected to the fixed portion. The fixed portion is capable of inserting into one of the slots to combine the fin assembly with the base. The fin portion includes a plurality of fins, and an interval is between the two adjacent fins. A largest length of each fin is less than one tenth of a wavelength of a noise frequency generated by the fin assembly.

BACKGROUND OF THE DISCLOSURE

1. Field of the Disclosure

The present disclosure relates to a heat dissipation device; more particularly, it relates to a heat dissipation device for avoiding the electromagnetic radiation spilling.

2. Description of the Related Art

The electronic device easily generates lots of heat because of the operation of the internal IC chips; therefore, the electronic device must work with a heat dissipation device, to dissipate the surplus heat to the outside of the electronic device. The common fixed heat dissipation device usually includes a plurality of heat dissipation fins. The heat dissipation fins are located on the IC chip which generates the heat, and working with the heat conducting element, such as a fan or a fluid pipes, to achieve the heat dissipation function.

However, after the heat dissipation fins made of the metal material contacts to the IC chip, the heat dissipation fins equals to an antenna device. When the IC chip works, the IC chip will affect the heat dissipation fins so as to generate an antenna effect to cause the problem of the electromagnetic radiation spilling. To solve the above problem, some heat dissipation devices adds a ground element. The heat dissipation fins can be grounded by the ground element to reduce the voltage and the capacitance of the fins, so as to reduce the electromagnetic radiation spilling. Since the heat dissipation fins are very close to the IC chip, so that the current in the IC chip is easily to couple to the heat dissipation fins; therefore, the electromagnetic radiation spilling can be still caused. Besides, the ground element of the common heat dissipation device is limited to only fasten to a specific locating position. Therefore, if the design of the IC chip or the circuit board is changed, different heat dissipation device must be selected to use so as to increase the cost of production.

Therefore, it is worthy to research to improve the heat dissipation device to avoid the electromagnetic radiation spilling.

SUMMARY OF THE DISCLOSURE

It is an object of the present disclosure to provide a heat dissipation device for avoiding the electromagnetic radiation spilling.

To achieve the abovementioned object, the heat dissipation device of the present disclosure includes a base and a plurality of fin assemblies. The base includes a plurality of slots. Each fin assembly includes a fixed portion and a fin portion connected to the fixed portion. The fixed portion is capable of inserting into one of the slots to combine the fin assembly with the base. The fin portion includes a plurality of fins, and an interval is formed between the two adjacent fins. A largest length of each fin is less than one tenth of a wavelength of a noise frequency generated by the fin assembly.

The heat dissipation device of the present disclosure further includes a ground element. The ground element includes a ground end and a combining end, and the base further includes at least one corresponding junction. The combining end of the ground element is connected to any one of the at least one corresponding junction of the base, and the ground end of the ground element is connected to a ground plane of the electronic device.

Accordingly, the largest length of each fin is limited by the structure design of the present disclosure, so that each fin is unable to satisfy the conditions of generating the noise frequency; therefore, the present disclosure can avoid each fin assembly to generate the noise frequency caused by the antenna effect. With the design of the ground element which can be located arbitrarily, the present disclosure can further avoid the problem of the electromagnetic radiation spilling.

BRIE DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an exploded view of the heat dissipation device of the present disclosure.

FIG. 2 illustrates a lateral view of the heat dissipation device located on the heating element of the electronic device of the present disclosure.

FIG. 3 illustrates a schematic drawing of the fin assembly of the heat dissipation device in different embodiments of the present disclosure.

FIG. 4A illustrates an experimental result schematic drawing for the electric field strength of the horizontal polarization when the length of each fin of the fin assembly of the heat dissipation device of the present disclosure is conformed to generate the noise frequency.

FIG. 4B illustrates an experimental result schematic drawing for the electric field strength of the vertical polarization when the length of each fin of the fin assembly of the heat dissipation device of the present disclosure is conformed to generate the noise frequency.

FIG. 5A illustrates an experimental result schematic drawing for the electric field strength of the horizontal polarization when the length of each fin of the fin assembly of the heat dissipation device of the present disclosure is not conformed to generate the noise frequency.

FIG. 5B illustrates an experimental result schematic drawing for the electric field strength of the vertical polarization when the length of each fin of the fin assembly of the heat dissipation device of the present disclosure is not conformed to generate the noise frequency.

FIG. 6A illustrates a schematic drawing of the ground element of the heat dissipation device in a second embodiment of the present disclosure.

FIG. 6B illustrates a schematic drawing of the ground element of the heat dissipation device in a third embodiment of the present disclosure.

FIG. 7 illustrates a schematic drawing of the application for the ground element of the heat dissipation device connected to the base in the second embodiment of the present disclosure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

These and other objects and advantages of the present disclosure will become apparent from the following description of the accompanying drawings, which disclose several embodiments of the present disclosure. It is to be understood that the drawings are to be used for purposes of illustration only, and not as a definition of the disclosure.

The heat dissipation device of the present disclosure can be applied to an electronic device with the cooling requirement, and the heat dissipation device of the present disclosure is located on a heating element of the electronic device. The electronic device can be a computer, a portable device, or other similar electronic device with the similar heating element, but the present disclosure is not limited to this.

Please refer to FIG. 1 and FIG. 2. FIG. 1 illustrates an exploded view of the heat dissipation device of the present disclosure; FIG. 2 illustrates a lateral view of the heat dissipation device 1 located on the heating element 81 of the electronic device 80 of the present disclosure.

As shown in FIG. 1 and FIG. 2, the heat dissipation device 1 of the present disclosure is used for locating on the heating element 81 of the electronic device 80, for providing the heat dissipation function. The heat dissipation device 1 of the present disclosure comprises a base 10 and a plurality of fin assemblies 20, and the base 10 and the plurality of fin assemblies 20 are all made of metal material. A bottom face 101 of the base 10 is connected to the heating element 81 for heat conducting, wherein a heat conducting medium 90 can be located between the bottom face 101 of the base 10 and the heating element 81, to increase the heat conducting effect between the base 10 and the heating element 81. A top face 102 of the base 10, which is relative to the conduction surface of the heating element 81, comprises a plurality of slots 11 for combining with the plurality of fin assemblies 20. The plurality of slots 11 are located substantially parallel to each other along a plane, and the plurality of slots 11 are arranged equidistantly, but the present disclosure is not limited to this. The locating and the arranging type of the plurality of slots 11 can be changed according to different requirements.

Each slot 11 comprises at least one opening end 111, such that each slot 11 can at least connect to a side face 103 of the base 10. Each fin assembly 20 can be inserted into each slot 11 correspondingly from the opening end 111 along a locating direction which is substantially horizontal. In one embodiment of the present disclosure, each slot 11 passes through from the side face 103 of the base 10 to the other opposite side face, so that each slot 11 forms two opening ends 111. Therefore, the fin assembly 20 can be inserted into the slot 11 from, any one of the opening ends 111 for combining the fin assembly 20 with the base 10.

In one embodiment of the present disclosure, each slot 11 comprises an opening part 112 and a containing part 113. The opening part 112 extends towards the bottom face 101 from the top face 102 of the base 10, so as to connect to the containing part 113. A section width w1 of a first section of the opening part 112 which is substantially vertical to the locating direction, is less than a section width w2 of a second section of the containing part 113 which is substantially vertical to the locating direction. The design of the opening part 112 coordinating to the containing part 113 is used for helping to fix the fin assembly 20 which inserts to the slot 11, but the structure of the slot 11 is not limited to this.

Each fin assembly 20 comprises a fixed portion 21 and a fin portion 22, and the fin portion 22 connects to the fixed portion 21. The structure of the fin portion 22 is corresponded to the opening part 112 of the slot 11; it means that the section width w1 of the opening part 112 of the slot 11 along the direction vertical to the locating direction is corresponded to a section width of the fin portion 22 of the fin assembly 20 along the direction vertical to the locating direction. The fixed portion 21 can be inserted to any one of the corresponding slot 11 of the base 10 for combining the fin assembly 20 with the base 10. The structure of the fixed portion 21 is corresponded to the containing part 113 of the slot 11; it means that the section width w2 of the containing part 113 of the slot 11 along the direction vertical to the locating direction is corresponded to a section width of the fixed portion 21 of the fin assembly 20 along the direction vertical to the locating direction. Accordingly, when each fin assembly 20 combines with the base 10, the fin assembly 20 and the base 10 can be fastened to each other, and each fin assembly 20 is prevented to be separated from the base 10 along the direction vertical to the locating direction.

Besides, the heat dissipation device 1 of the present disclosure further comprises a ground element 30. The base 10 is connected to a ground plane of the electronic device 80 via the ground element 30 for achieving a ground effect to reduce the electromagnetic radiation spilling. The ground plane can be a grounding area on the electronic device 80 or the case of the electronic device 80. The ground element 30 comprises a ground end 31 and a combining end 32. The ground end 31 is used for connecting to the ground plane of the electronic device 80. The ground end 31 is fastened to the ground plane via screwing or inserting. In this embodiment, the ground end 31 comprises a hole 311, and a screwing element 91 can pass through the hole 311 to fasten the ground element 30 on the ground plane. Besides, a distance between the ground end 31 and the combining end 32 can be changed according to a height of the heating element 81 and the base 10 for requirements.

The combining end 32 of the ground element 30 is used for connecting to the base 10. The base 10 further comprises at least one corresponding junction 12. Each structure of the corresponding junction 12 is corresponded to the combining end 32 of the ground element 30. In this embodiment, the combining end 32 of the ground element 30 forms a hooking structure, and the at least one corresponding junction 12 are a plurality of combining holes located on the periphery of the base 10. Therefore, for the different designs of the electronic device 80, the ground element 30 can be selected to locate to any one of corresponding junction 12. The ground element 30 is fastened to the selected combining hole via the hooking structure of the combining end 32. Therefore, the locating position of the ground element 30 can be changed according to the requirement to achieve the grounding effect.

Please refer to FIG. 3, which illustrates a schematic drawing of the fin assembly 20, 20′ of the heat dissipation device in the different embodiments of the present disclosure.

As shown in FIG. 3, each fin portion 22 or 22′ of the fin assembly 20 or 20′ comprises a plurality of fins 22 a or 22 a′, and the amount of the fins 22 a or 22 a′ of every single fin assembly 20 or 20′ can be changed according to different designs (such as the fin assembly 20 comprises two fins 22 a, and the other fin assembly 20′ comprises three fins 22 a′). An interval S or S′ is formed between the two adjacent fins 22 a or 22 a′, so that each fin 22 a or 22 a′ has a fin length L or L′. In this embodiment, for the single fin assembly 20 or 20′, the fin length L or L′ of each fin 22 a or 22 a′ of the same fin assembly 20 or 20′ are the same, but the present disclosure is not limited to this.

In this disclosure, each fin length L or U of the fin 22 a or 22 a′ of each fin assembly 20 or 20′ of the present disclosure is designed for avoiding producing the electromagnetic radiation spilling of the heat dissipation device 1. The electromagnetic radiation spilling of the heat dissipation device 1 is extremely relevant to the wavelength of the noise frequency generated by the heat dissipation device 1 affected by the heating element 81; therefore, the wavelength of the noise frequency which may be generated by the heat dissipation device 1 can be calculated via the following formula, and further infers that the largest length of the fin for avoiding the electromagnetic radiation spilling of the heat dissipation device 1. The formulas are as below:

$\begin{matrix} {f = \frac{d}{X_{c}\left( {2{\pi ɛ}\; A} \right)}} & (1) \\ {\lambda = \frac{C}{f}} & (2) \end{matrix}$

The λ is the wavelength of the noise frequency, which may be generated by the fin assembly 20; C is the light speed; f is the noise frequency, which may be generated by the fin assembly 20; X_(c) is the capacitive reactance generated by a contacting surface of the base 10 and the heating element 81; ∈ is a dielectric constant of the heat conducting medium 90 between the base 10 and the heating element 81; A is a contacting area between the base 10 and the heating element 81; d is a distance from the base 10 to the contacting surface of the heating element 81.

According to the formula (1), the noise frequency f generated by the heat dissipation device 1 of the present disclosure located on the heating element 81 can be calculated. According to the formula (2), the wavelength λ corresponded to the noise frequency f can be calculated. Therefore, according to the abovementioned formulas, the formula for calculating the wavelength λ corresponded to the noise frequency f is as below:

$\begin{matrix} {\lambda = \frac{{CX}_{c}\left( {2{\pi ɛ}\; A} \right)}{d}} & (3) \end{matrix}$

Finally, allowing the wavelength λ of the formula (3) to be divided by 10, to calculate the fin length L of the noise frequency f generated by the fin assembly; the formula is as below:

$\begin{matrix} {L = {\frac{\lambda}{10} = \frac{{CX}_{c}\left( {2{\pi ɛ}\; A} \right)}{10d}}} & (4) \end{matrix}$

It could be known that the fin length L of each fin 22 a for satisfying to generate the noise frequency f is one tenth of the wavelength of the noise frequency; therefore, in the structure design, the largest fin length of each fin 22 a must be less than one tenth of the wavelength of the noise frequency, to avoid generating the electromagnetic radiation spilling.

Please refer to FIG. 4A to FIG. SB. FIG. 4A illustrates an experimental result schematic drawing for the electric field strength of the horizontal polarization when the length L of each fin of the fin assembly 20 of the heat dissipation device 1 of the present disclosure is conformed to generate the noise frequency f. FIG. 4B illustrates an experimental result schematic drawing for the electric field strength of the vertical polarization when the length L of each fin of the fin assembly 20 of the heat dissipation device 1 of the present disclosure is conformed to generate the noise frequency f. FIG. 5A illustrates an experimental result schematic drawing for the electric field strength of the horizontal polarization when the length L of each fin of the fin assembly 20 of the heat dissipation device 1 of the present disclosure is not conformed to generate the noise frequency f. FIG. SB illustrates an experimental result schematic drawing for the electric field strength of the vertical polarization when the length L of each fin of the fin assembly 20 of the heat dissipation device 1 of the present disclosure is not conformed to generate the noise frequency.

In this embodiment, it assumed that the working frequency of the heating element 81 (such as an IC chip) is 822 MHz. The working IC chip can affect the heat dissipation device 1 of the present disclosure to generate the resonance; therefore, if the working frequency is considered as the noise frequency generated by the heat dissipation device 1 of the present disclosure, the wavelength λ, corresponded to the working frequency of the IC chip can be calculated as 36.5 cm via the abovementioned formula (2). The fin length L of the heat dissipation device 1 of the present disclosure for generating the noise frequency f can also be calculated as 3.65 cm via the formula (4). Therefore, in the design of this embodiment, the fin length L of each fin must be less than 3.65 cm.

As shown in FIG. 4A and FIG. 4B, if each fin length L of the fin of the heat dissipation device 1 of the present disclosure is 4.5 cm, the fin length L is higher than 3.65 cm which is the abovementioned fin length for generating the noise frequency f. When the IC chip works, the polarizing field strength value (dBuV/m) of the vertical and horizontal direction polarization in the corresponding frequency (such as the 822 MHz shown in Point 1), is higher than the limited setting which is 40 dBuV/m in this embodiment. Therefore, the noise frequency is easily to generated to cause the electromagnetic radiation spilling.

As shown in FIG. 5A and FIG. 5B, if the fin length L of each fin of the heat dissipation device 1 of the present disclosure is 2.5 cm, the fin length L is less 3.65 cm which is the fin length for generating the noise frequency f. When the IC chip works, the polarizing field strength value of the vertical and horizontal direction polarization in the corresponding frequency (such as the 822 MHz shown in Point 1), is obviously less than the limited setting which is 40 dBuV/m in this embodiment. Therefore, it can prevent effectively the noise frequency from being generated, and improve the problem of the electromagnetic radiation spilling.

Please refer to FIG. 6A to FIG. 7. FIG. 6A illustrates a schematic drawing of the ground element 30 a of the heat dissipation device in the second embodiment of the present disclosure. FIG. 6B illustrates a schematic drawing of the ground element 30 b of the heat dissipation device in the third embodiment of the present disclosure. FIG. 7 illustrates a schematic drawing of the application for the ground element 30 a of the heat dissipation device connected to the base in the second embodiment of the present disclosure.

As shown in FIG. 6 A, in this embodiment, the combining end 32 a of the ground element 30 a of the heat dissipation device 1 disclosure can be changed. The combining end 32 a comprises a first member 321 a and a second member 322 a connected to the first member 321 a, and an angle is formed between the second member 322 a and the first member 321 a, so that the combining end 32 a forms a bent structure; wherein the angle between the first member 321 a and the second member 322 a is between 0° to 180°. In this embodiment, the first member 321 a is a plate member which extends along a substantially horizontal direction, and the second member 322 a is another plate member which extends along a substantially vertical direction; therefore, the angle formed between the first member 321 a and the second member 322 a of the bent structure is 90°. The ground element 30 a can be fastened on the base via the bent structure.

As shown in FIG. 6A and FIG. 7, in order to corresponding to the design of the combining end 32 a of the ground element 30 a, the corresponding junction 12 a of the base 10 a is a chute structure in this embodiment. The chute is located on a side face 104 a and extending inwardly from the side face 104 a. The next side face 103 a comprises an opening end for combining the abovementioned combining end 32 a of the ground element 30 a to slide along the chute. The chute comprises a first groove 121 a and a second groove 122 a connected to the first groove 121 a, and an angle is formed between the second groove 122 a and the first groove 121 a so as to form a bending groove. The structure design of the chute is corresponded to the combining end 32 a of the ground element 30 a, so that the first member 321 a of the combining end 32 a is corresponded to the first groove 121 a of the chute, and the second member 322 a of the combining end 32 a is corresponded to the second groove 122 a of the chute. Therefore, the combining end 32 a of the ground element 30 a can slide into the corresponding junction 12 a of the base 10 a, and optionally move to any position along the corresponding junction 12 a, for the location requirements of different electronic devices.

As shown in FIG. 6B, in this embodiment, the ground element 30 b of the heat dissipation device is designed based on the ground element 30 a shown in FIG. 6A. The originally ground end 32 a having the hole 311 a can be replaced by an inserting structure, so that the ground end 32 b is able to directly insert into a corresponding aperture of the ground plane of the electronic device; the ground end 32 b of the ground element 30 b can be fastened without any screwing element or other fixed element.

Via the module design of the fin of the heat dissipation device of the present disclosure, the fin length can be limited, so that each fin is not affected by the heating element to generate the noise frequency; therefore, the problem of the electromagnetic radiation spilling can be solved. The heat dissipation device of the present disclosure also provide a flexible design for disposing the ground element. Accordingly, the heat dissipation device of the present disclosure can be applied to any electronic devices with the heating element which has the different working frequency, size, and height.

It is noted that the above-mentioned embodiments are only for illustration. It is intended that the present disclosure cover modifications and variations of this disclosure provided they fall within the scope of the following claims and their equivalents. Therefore, it will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present disclosure without departing from the scope or spirit of the disclosure. 

What is claimed is:
 1. A heat dissipation device, located on a heating element, the heat dissipation device comprising: a base, comprising a plurality of slots; and a plurality of fin assemblies, each of the fin assemblies comprising a fixed portion and a fin portion; the fin portion being connected to the fixed portion, and the fixed portion being capable of inserting into one of the plurality of slots to combine the fin assembly with the base; the fin portion comprising a plurality of fins, an interval being formed between the two adjacent fins, and a largest length of each of the fins is less than one tenth of a wavelength of a noise frequency generated by the fin assembly.
 2. The heat dissipation device as claimed in claim 1, wherein the wavelength of the noise frequency generated by the fin assembly is obtained via a formula: $\lambda = \frac{{CX}_{c}\left( {2{\pi ɛ}\; A} \right)}{d}$ wherein λ is the wavelength the of noise frequency generated by the fin assembly; C is a light speed; X_(c) is a capacitive reactance generated by a contacting surface between the base and the heating element; ∈ is a dielectric constant of a thermal material located between the base and the heating element; A is a contacting area between the base and the heating element; d is a distance from the base to the contacting surface of the heating element.
 3. The heat dissipation device as claimed in claim 1, wherein each of the slots comprises at least one opening end, and the fin assembly is inserted into the slot along a locating direction which is substantially horizontal from any one of the opening ends of the slot.
 4. The heat dissipation device as claimed in claim 3, wherein each of the slots comprises an opening part and a containing part; a section width of the opening part which is substantially vertical to the locating direction, is less than a section width of the fixed portion of the containing part which is substantially vertical to the locating direction.
 5. The heat dissipation device as claimed in claim 4, wherein a section width of the fixed portion of the fin assembly which is vertical to the locating direction, is corresponded to a section width of the containing part which is vertical to the locating direction; a section width of the fin portion of the fin assembly which is vertical to the locating direction, is corresponded to a second section width of the opening part which is vertical to the locating direction.
 6. The heat dissipation device as claimed in claim 5, further comprising a ground element, the ground element comprising a ground end and a combining end, and the base further comprising at least one corresponding junction, wherein the combining end of the ground element is connected to one of the at least one corresponding junction of the base, and the ground end is connected to a ground plane.
 7. The heat dissipation device as claimed in claim 6, wherein the at least one corresponding junction is at least one chute, and each of the chutes is located on one side of the base; each chute comprises at least one opening end, for combining with the combining end of the ground element; the combining end of the ground element can optionally move to any position along the chute.
 8. The heat dissipation device as claimed in claim 7, wherein each of the chutes further comprises a first groove and a second groove connected to the first groove, and an angle is formed between the second groove and the first groove; the combining end of the ground element comprises a first member corresponding to the first groove and a second member corresponding to the second groove, and the second member is connected to the first member and the angle is formed between the second member and the first member.
 9. The heat dissipation device as claimed in claim 6, wherein the ground end of the ground element is fastened to the ground plane via screwing or inserting.
 10. The heat dissipation device as claimed in claim 6, wherein the combining end forms a hooking, and the at least one corresponding junction is a plurality of combining holes located around the base; the combining end of the ground element can be optionally connected to any one of the combining holes for changing a locating position of the ground element.
 11. The heat dissipation device as claimed in claim 1, further comprising a ground element, the ground element comprising a ground end and a combining end, and the base further comprising at least one corresponding junction, wherein the combining end of the ground element is connected to one of the at least one corresponding junction of the base, and the ground end is connected to a ground, plane.
 12. The heat dissipation device as claimed in claim 11, wherein the at least one corresponding junction is at least one chute, and each of the chutes is located on one side of the base; each chute comprises at least one opening end, for combining with the combining end of the ground element; the combining end of the ground element can optionally move to any position along the chute.
 13. The heat dissipation device as claimed in claim 12, wherein each of the chutes further comprises a first groove and a second groove connected to the first groove, and an angle is formed between the second groove and the first groove; the combining end of the ground element comprises a first member corresponding to the first groove and a second member corresponding to the second groove, and the second member is connected to the first member and the angle is formed between the second member and the first member.
 14. The heat dissipation device as claimed in claim 11, wherein the ground end of the ground element is fastened to the ground plane via screwing or inserting.
 15. The heat dissipation device as claimed in claim 11, wherein the combining end forms a hooking, and the at least one corresponding junction is a plurality of combining holes located around the base; the combining end of the ground element can be optionally connected to any one of the combining holes for changing a locating position of the ground element. 